1. Field of the Invention
The present invention relates to a fuel pressure control system for a high pressure fuel injection engine which immediately reduces the fuel pressure in the high pressure line of the fuel system to suppress a blowout of fuel from a damaged part in the high pressure line when a car body receives a strong impact.
2. Related Art of the Invention
Generally, most of such high pressure fuel injection engines, when operating, continuously regulates a predetermined line pressure by a high pressure regulator and control an amount of injected fuel by fuel injection timing.
When a car body receives a sudden impact in, for example, a collision and the high pressure line is damaged from the impact, fuel in the high pressure line may blow out from the damaged part.
As conventional means for reducing the fuel pressure, Japanese laid open utility model application No. 57-25157, for example, discloses a system momentarily stopping or reducing fuel delivery to an injector when the fuel pressure in the high pressure line is abnormally high and a relieving system for the fuel pressure out of the high pressure line to reduce the fuel pressure when an engine stop is detected.
It is contemplated as a technique of preventing the blowout of fuel from the high pressure line of a fuel system where damage is detected, wherein the line pressure and fuel system immediately relieves the fuel pressure when the line pressure is rapidly reduced.
However, the fuel pressure in the high pressure line is so high that a considerable amount of the fuel has already been blown out of the damaged part in the fuel system when the fuel pressure reduction is detected. Thus, the fuel blowout cannot be prevented even if the fuel pressure is reduced after the detection of the line damage.
In addition, since the fuel system must accurately detect a small change in the line pressure in order to early detect damage in the high pressure line, the fuel system tends to provide a maldetection, which provides trouble for the normal running of a car.